h THE NOBTH AMERICAN SFEGIES OF A8TEEELLA. By Alexander W. Evans. DfTBODTJCTIOH. The genus Asterella was published by Palisot de Beauvois, prob- ably in 1805,1 and was based on the two Dillenian species, " Lichen pileatus parvus carinatus, capitulis fimbriatis " and " Lichen pileatus parvus, foliis crenatis."8 In the first edition of his Species Plant- arum (1753) Linnaeus had recognized both of these species and had included them in his composite genus Marchwitia, giving them the binomial names M. tenella and M. h emispluicrica. Palisot de Beau- vois accepted these specific names and designated his two species Asterella tenella and A. kemisphaeivca. According to modern ideas the genus as originally defined was a composite, its two species no longer being considered congeneric. In spite of this fact it was ade- quately published and deserves recognition in a restricted sense, if the current rules of nomenclature are followed. Botanists, however, persistently ignored its claims for over 50 years, and many refuse to admit their validity even at the present time. This is due partly to the confusion caused by Lindberg and Trevisan in their attempts to reestablish the genus and partly to the fact that two other genera, proposed for the reception of the Linnaean M. tenella and M. hemi- sphaerica, had come in wide use. The genera in question are Reboulm and Fimbriaria. Reboxtiia was published by Raddi in 1818* and was based on M. hemisphaerica; Fimbriaria was published by Nees von Esenbeck in 1820 * and in- cluded M. tenella and three other species. If Raddi had known of Palisot de Beauvois's genus and had recognized its composite nature, the establishment of a new genus upon either of its component species 1 Lam. Diet Sci. Nat 3: 257. 1805 (?). This citation has been kindly sup- plied by Dr. John Hendley Barnhart, of the New York Botanical Garden. Dr. Barnhart states that the date Is somewhat doubtful but that the volume cited could not have been published later than 1806. * Hist Muse. 521. pi. 75, f. k*> 519. pk 75, f. 2. 1741. *Opusc. Set, Bologna 2: 357. 1818. The name was originally spelled « RebvuillUt." *Hor. Phys. Berol. 44. 1820. The name wns originally spelled " Fimbraria." 247 248 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. I would have been a perfectly justifiable procedure, and the name A8terella would naturally have been reserved for the remaining species. Even in the absence of such knowledge the retention of the name for A. tenella is logically demanded, according to the Vienna Rules, since Rebovlia preceded Fimbnaria by two years. Nees von Esenbeck's genus would then naturally lapse into synonymy, since the other species included in Fimbriarm are all congeneric with A. tenella. These conclusions seem inevitable and were clearly stated by Underwood1 over 20 years ago. Unfortunately Lindberg,' when he revived the genus Asterella in 1868, restricted the name to A. hemisphaerica instead of to A. tencUa, although he gives no reason for so doing. Six years later Trevisan,8 in ignorance of Lindberghs action, revived AstereU-a independently, referring to it five species, all congeneric with A. tenella. Soon after- wards, however, upon learning of Lindberghs work, he adopted the genus Asterella in the Lindbergian sense and revived Cord a's genus Hypenantron for A* tenella and its allies,4 the name Fimbnaria in his opinion being untenable. At almost the same time Lindberg * also changed, and used Asterella in the sense originally suggested by Trevisan (that is, for A. tenella and its allies), the name Reboulia thus again becoming available for A. hsmisphasrica. These facts are set forth with much ridicule by Le Jolis,6 who advocates the abandonment of the name AstereUa altogether on account of the dif- ferent senses in which it has been used, not only by different writers but by the same writers at different times. His arguments would perhaps have more weight if Palisot de Beauvois himself, rather than his successors, had been responsible for the confusion. Since this is not the case, there seem to be no adequate reasons for giving up the name but many good reasons for retaining it in the sense originally suggested by Trevisan, a course which recent writers in America and Scandinavia have consistently maintained. At the same time most European writers still prefer Fimbnaria; and both Stephani and Schiffner, at the Brussels Congress in 1910, definitely recommended that Fimbviavia and Reboulia be placed among the nomina c&mervanda, to the exclusion of Asterella. Of the four species originally assigned to Fimbriaria the first, which may be regarded as the type of the genus, was the African F. marginata Nees, the remaining species being F. fragrans Nees, F. saecata (Wahl.) Nees, and F, tenella (L.) Nees. During the next 1 Bot Gaz. 00: 59. 1896. * Not Sailsk. Faun. Fl, Fenn. Fiirh. 9: 280. 1868. •Rend. 1st. Lombardo II. 7: 785. 1874. 4 Mem. iBt. Lombardo III. 4: 440. 1877. •Hep. Utveckl. 49. 1877. * M6m. Soc. Scl. Nat. Cherbourg 29: 131. 1895. EVANS—THE NORTH AMERICAN SPECIES OF ASTKRELLA. 249 quarter century the genus gradually increased in size, partly through the transfer of species from other genera and partly through the addition of new species. When the Synopsis Hepaticarum was pub- lished in 1847 the number of species recognized had grown to 24. Five of these were recorded from Europe only, 4 from Africa, 7 from Asia, and 2 each from North America, South America, and Australasia; the two remaining species were reported from both Eu- rope and North America, one of them also from Asia. When Stephani published his monograph of the genus in 1899,1 the num- ber of species, in spite of certain reductions to synonymy, had more than doubled, 69 being recognized. Three of these are recorded from Europe only, 14 from Africa, 15 from Asia, 16 from North America, 7 from South America, and 11 from Australasia and the Hawaiian Islands; the remaining three species are reported from both Europe and North America, one being reported in addition from Asia, and one from South America. According to the records at hand 28 species, 5 from Africa, 11 from Asia, 3 from North America, 3 from South America, and 6 from the Pacific islands, have been published since 1899, thus raising the total to 97. The majority of these additions were made by Stephani in the sixth volume of his Species Hepaticarum (1917). The writer hopes to show, however, that several of the species recognized by Stephani should be reduced to synonymy, and it is possible that others deserve the same fate. Trevisan's attempt to replace Fimbriaria by Hypenantron was based on the existence of an older algal genus Fi?nbriaria, published by Stackhouse in 1809. Since this name was soon repudiated by its author and has been ignored by practically all later algologists, Le Jolis claims that it has no nomenclatorial standing, and that it ought not to stand in the way of maintaining Fimbriaria Nees as a valid genus. Fortunately the adoption of AstereUa makes it unnecessary to decide this point. Hypenantron as originally described by Corda * contained a single species, the Swiss H, ciliatum, Since no descrip- tion of this species is given, other than that included in the generic diagnosis, its identity would be in doubt if Nees von Esenbeck * had not listed it among the synonyms of Fimbriaria fragrcms. Follow- ing the example of Trevisan, certain European writers recognized Hypenantron for a while, but it enjoyed a short-lived vogue and has few or no adherents at the present- time. Two other synonyms, Rhaeotheca Bisch. of 1844 * and Octoshepos Griffith of 1849,6 remain to be considered. Hhacotheca was based on 1 Bull. Herb. Boiss. 7: 84-110, 198-214. 1899. *Oplz, Beitr. Naturg. 648. 1828. * Naturg. Eur. Leberm. 4: 268. 1838. * Seubert, Fl. Azor. 12. pi. 1J. 1844. 'Not PI. Aelat. 2: 343; Icon. PI. Aslat. 2: pi. 69D, f. 1 1849. 250 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. a single species of the Azores, i?. azorica Bisch., and was admitted into the Synopsis Hepaticarum and several subsequent works. Schiff- ner reduced the genus to synonymy in 1893,1 and its single species is now considered identical with Fimbriaria africa/na Mont., or Asterella africcma (Mont.) Underw., as it should be called, a species known from Madeira, the Canary Islands, and Algeria, as well as from the Azores. Oetoshepos was likewise a monotypic genus, being based on 0. kkasianus Griffith, of the Himalayas. Mitten, in 1861,a reduced it to synonymy under Fimbriaria, to which genus he trans- ferred the single species, and it is retained in this position by Stephani. Of the North American species recognized by Stephani in his monograph the following eight were originally described by Ameri- can writers: A. bolanderi, A. pafoneri, and A. violacea by Austin; A. austini, A. pringlei, and A. wnghtii by Underwood; A. lateralis and A. nudata by Howe. The remaining species were all described by Europeans. Soon after the appearance of Stephani's mono- graph Howe8 published an account of the species occurring in Cali- fornia and found it necessary to reduce A. nudata to synonymy un- der A. pahneri. His treatment of the genus, which is remarkably full and clear, is accompanied by detailed illustrations of most of the Californian species and has been of great assistance to the writer in the preparation of the present report. M0BFH0L0QICAL NOTES ON THE GENUS. The species of Asterella grow on earth, often among rocks, and sometimes form depressed mats of considerable extent. Although the genus has many tropical representatives, it extends as far south as Chile, Australia, and New Zealand, and as far north as Green- land, Alaska, Siberia, and Scandinavia.